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Category Archives: Development

Postman is a popular tool for crafting up and making HTTP requests. It makes calling REST/JSON APIs like the Microsoft Graph etc… much easier. Over the years I learnt a couple of tricks that make using postman and the graph much easier that a couple of people have asked me about after seeing them in demos. So here goes.

#1. Use variables

The first thing you need to do before calling an API like MS Graph is to Authenticate. This involves app ids, secrets, tokens and other magic strings. Rather than pasting these into your requests you can set up an environment in postman that contains variables that define all these.

In an environment you can define variables like your appId, secret, tenant name etc…

Then in your requests you can use those variables, rather than copying them in, like in this call to get an access token for app-only (aka: client credential flow) calls:

Notice in the places where I need to insert these variables you use the {{ variable_name }} syntax.

#2. Automatically cache tokens

In the call made above to get an app-only access token for the graph the response payload would look like this:

Normally you would need to copy that access token out and save it into a variable for use in other calls. However, using postmans ability to run “tests” after responses come back you can run a bit of javascript that saves the content of the token into a variable automatically.

Here is the javascript:

This will run after your request is made and grabs the access token from the response and saves it in the appOnlyAccessToken variable.

Then you can make other graph calls like this one to get all users in a tenant using that variable.

Postman has built in support for helping with authentication such as OAuth etc… however i have never found it to be particularly reliable. Also you can use this same technique for other variables like a users id etc…

I had a great time speaking at Microsoft’s Ignite conference last week! It was fun talking a bit about our startup journey at Hyperfish and some of the decisions we made along the way about running and supporting our service.

This was a totally new topic for me and something a bit outside my normal speaking topics … but I really enjoy sharing our journey with others!

Sometimes hosted build agents in VSTS dont cut the mustard and you want full control over your build environment. That’s where self hosted build agents come in. The problem is … do you don’t want to run VMs ideally and if you are getting into Kubernetes then your dev cluster is probably sitting there idle 90%+ of the time with all those CPU cycles being wasted.

We decided to do something with that extra capacity and run a set of VSTS linux build agents (good for Nodejs and .net Core builds etc…) in our dev AKS cluster! We can scale them up for more concurrent builds really easily.

Helm is a tool that helps you install apps in your kubernetes environment. Helm charts are templates for your application. They define what your app needs and what containers should be deployed etc… Fortunately Microsoft make their linux build agent available as a Docker image that we can use in a helm chart to get it deployed. https://hub.docker.com/r/microsoft/vsts-agent/

This means all we need to do is deploy it (or many of them) to Kubernetes … and helm charts can help with that! We wrote a basic one to get things going.

We recently moved our production service to the new Azure Kubernetes Service (AKS) from Microsoft. AKS is a managed Kubernetes (K8s) offering from Microsoft, which in this case, means Microsoft manage part of the cluster for you. With AKS you pay for your worker nodes, not your master nodes (and thus control plane) which is nice.

Why did we move

The short story is that we were forced to evaluate our options as the current orchestration software we were using to run our service was shutting down. Docker Cloud was a sass offering that offered capabilities around orchestration/management or our docker container based service. This meant we used it for deployment of new containers, rolling out updates, scheduling those containers on various nodes (VMs) and keeping an eye on it all. It was a very innovative offering 2 years ago when we started using it, was cloud based, easy to use and price competitive. Anyway, Docker with their new focus on making money the Enterprise decided to retire the product and we were forced to look elsewhere.

Kubernetes was the obvious choice. It’s momentum in the industry means there are a plethora of tools, guidance, community and offerings around it. Our service was already being run in Docker containers and so didn’t require significant changes to run in Kubernetes. Our service is comprised of ~20 or so “services” e.g. frontend, API. Kubernetes helps you run these services. It offers things like scheduling those containers to run, managing spinning up new ones if they stop etc.

Every major cloud provider has a Kubernetes offering now. Googles GKE has been around since as early as Nov 2014 & Amazon’s AWS recently released their EKS (on June 2018).

Choosing AKS

We are not a big team and we couldn’t afford to have a dedicated team to run our orchestration and management platform. We needed an offering that was run by Kubernetes experts who know the nitty gritty of running K8s. The team building AKS at Microsoft are those people. Lead by the co-founder of the Kubernetes project Brendan Burns the MS team know their stuff. It was compelling that they were looking at new approaches in the managed K8s space like not charging for the control plan/master nodes in a cluster and were set on having it just be vanilla K8s and not a weird fork with proprietary peculiarities.

Summary of reasons (in no particular order):

Azure based. Our customers expect the security and trust that Microsoft offers. Plus we were already in Azure.

Managed offering. We didn’t want to have to run the cluster plumbing.

Cost. Solid price performance without master node costs.

Support. Backed by a team that know their stuff and offer support (more on this below).

AKS is relatively new and at the time we started considering our options for the move AKS was not a generally available service. We didn’t know when it would GA either. This pained me to say the least, but we had a hunch it was coming soon. To mitigate this we investigated acs-engine which is a tool that AKS uses behind the scenes to generate ARM templates for Azure to stand up a K8s cluster. Our backup plan was to run our own K8s cluster for a while until AKS went GA. Fortunately we didn’t need to do this 🙂

Moving to Kubernetes

We were in the fortunate position that our service was already running in a set of Docker containers. Tweaking these to run with Kubernetes only required minor changes. Those were all focused on supplying configuration to the containers. We used a naming convention for environment variables that wasn’t Kubernetes friendly, so we needed to tweak the way we read that configuration in our containers.

The major work required was in defining the “structure” of our application in Kubernetes configuration files. These files define the components in your application, the configuration of them, how they can be communicated with & resources they need. These files are just YAML files however manually building them can be tedious when you have quite a few to do. Also there can be repetition between them and keeping them in sync can be painful.

Helm is the “package manager for Kubernetes” … but I prefer to think of it as a tool that helps you build templates (“charts”) of your application.

In Azure speak they are like ARM templates for your application definition.

The great part about Helm is that it separates the definition of your application and the environmental specifics. For example, you build a chart for your application that might contain a definition for your frontend app and an API, what resources they need and the configuration they get e.g. DB connection string. But you don’t have to bake the connection string into your chart. That is supplied in an environment specific values file. This lets you define your application and then create environment specific values files for each environment you will deploy your application to e.g. test, stage, production etc. You can manage your chart in source control etc. and manage your environment specific values files (with secrets etc.) outside of source control in a safe location.

This means we can deploy our service on a developer laptop, AKS cluster in Azure for test or into Production using the exact same definition, but with different environment specific configuration.

Chart + Environment config == Full definition.

We already had a Docker Compose definition of our service that our engineers used to run the stack locally during development. We took this and translated it into a Helm chart. This took a bit of work as we were learning along the way, but the result is excellent. One definition of our service in a declarative, modular and configurable way that we use across development, test environments and production.

Helm charts are already available for loads of different applications too. This means if you want to run apps like redis, postgres or zookeeper you don’t have to build your own helm charts.

That’s a lot of words … what’s the pay off Chris?

The best way I can demonstrate in a blog post the value all this brings is to show you how simple it is to deploy our application.

Two commands to a fully functional environment, running on a 4 node K8s cluster in Azure. Not bad at all!! It takes us about 10 mins to spin up depending on how fast Azure is at provisioning nodes.

What didn’t go well

Of course there were things that didn’t go perfectly along with all this too. Not specifically AKS related, but Azure related. One in particular that really pissed me off 🙂 During the production move we needed to move some static IP addresses around in our production environment. We started the move and it seemingly failed part the way through the move. This left our resource group in Azure locked for ~4 hours!! During this time we couldn’t update, edit or add anything to our resource group. We logged a Severity A support ticket with MS which is supposed to have a 1 hour response time … over 3 hours later we were still waiting. We couldn’t wait and needed to take mitigation steps which included spinning up a totally new and separate environment (easy with AKS!) and doing some hacky things with VMs and HAProxy to get traffic proxied correctly to it. Some of our customers whitelist our static IP addresses in their firewalls so we don’t have the luxury of a simple DNS change to point at a new environment. It was disappointing to say the least that we pay for a support contract from MS but Azure failed and more importantly our support with MS failed and left us high and dry for 4 hours. PS: they still don’t know what happened, but are investigating it.

Summary

Docker closing it’s Docker Cloud offering was the motivation we needed to evaluate Kubernetes and other services. It left me with a bad taste in my mouth with Docker as a company and I will find it hard to recommend or trust taking a dependency on a product offering from them. Deprecating a SaaS product with 2 months notice is not the right way to operate a business if you are interested in keeping customers IMHO. But nevertheless a good thing for us ultimately!

Our experience moving to AKS has been nothing short of excellent. We are very glad the timing of AKS worked in our favor and that Microsoft have a great offering that meets our needs. It’s still early days with AKS and time will be the ultimate proof, however as of today we are very happy with the move.

If you are new to container based applications and are from a Microsoft development background I recommend checking out a short tutorial on ASP.Net + Docker. I have thoroughly enjoyed building a SaaS service that serves millions of users in a container based model and think many of the benefits it offers are worth considering for new projects.

If you want to learn Kubernetes in Azure I recommend their getting started tutorial. It’s will give you a basic understanding of K8s and how AKS works.

Finally … I interviewed Gabe Monroy from the AKS team when I was at Build 2018 for the Microsoft Cloud show if you are interested in hearing more about AKS, the team behind it and Microsoft’s motivations for building it!

What a fun few days hanging out with friends and collegues in Las Vegas for the last few days. SPC NA seemed to go pretty well! I think the biggest thing for me this week was being surrounded by people who all share a common passion. That is what SPCs in the past were great at and i think some of that was rekindled this week. As always wandering the expo floor and talking with other vendors about what they are building is my favorite thing about conferences and this week was great for that. Some new faces popped up too!

For those looking for my slides from the session i did you can find them below. Unfortunatly there is a lot of content in the demos that isnt captured in the slides, but i hope it helps.

Many years back a small group of friends started the Office 365 developer slack network. A bunch of people joined and then it rapidly went nowhere

I think that is a crying shame.

I recently joined a Slack network for Kubernetes and its a fantastic resource for asking people questions, working with others on issues you are having and generally learning and finding things.

Office 365 development has changed a lot over the years and people are finding new ways of doing things all the time. The Microsoft Graph is taking off in a HUGE way, SPfx is becoming a viable way to build on the SharePoint platform, Azure AD is the center of everything in the cloud for MS and the ecosystem is heating up with amazing new companies and products springing up.

Anyway … I miss having a Slack network for Office 365 development chats with people.

Photos in Office 365 are a pain. This is because there are currently three(!) main places photos are stored in Office 365:

SharePoint Online (SPO

Exchange Online (EXO)

Azure Active Directory (AAD)

If you are syncing profiles using AD Connect those profiles are being synced into AAD. From there they take a rather arduous and rocky path to EXO and SPO via a number of intermediatary steps that may not work or may only complete after a period of time. e.g. from EXO to SPO photos may only sync if someones photo has not been set directly in SPO and a rather profile property attribute is not set correctly.

Needless to say it can be very hard to work out why you have one photo in AD on-prem, one in AAD, one in EXO and another in SPO … all potentially different!

At Hyperfish we built our product to push photos to all the places they should go when someone updates them. This means that when someone updates their photo and that update is appoved that it will be resized appropriately for each location and then saved into AD, EXO and SPO immediately. This results in the persons photo being the same everywhere at the same time. Happy place!

However, we have some customers who want to bulk move/copy photos around between these different systems to get things back in order all at once. To do this we created a helpful wee commandline utitility that we have published the source code for on GitHub and a precompiled release if you dont want to compile it yourself.

Photo Importer Exporter

Creative naming huh! 🙂

The Photo Importer Exporter is a very basic Windows command line utility that lets you:

Export photos from SharePoint Online

Export photos from Exchange Online

Import photos to Active Directory

Import photos to SharePoint Online

Import phtoso to Exchange Online

All you do is Export the photos from, say, Exchange Online (the highest resolution location) and it will download them all to the /photos directory. Then you can Import them to, say, Active Directory and the utility will resize them appropriately and save them to AD for you. Simple huh.

The issue with just firing up Fiddler and watching traffic is that to decrypt HTTPS traffic fiddler installs a root certificate so that SSL is terminated in Fiddler first so that it can show you the decrypted payloads back and forth etc…

That is normally fine with apps that use the standard WinINET libraries etc… to make HTTPS calls (like chrome). However, Azure Storage Explorer an Electron app using NodeJS and doesnt use these. Node also handles root CAs a bit differently and a long story short is that it doesn’t by default trust Fiddlers Root Cert that it installs. This means that HTTPS calls fail with a “unable to verify the first certificate” error.

Setting up Fiddler

First you need to set up Fiddler to decypt HTTPS traffic. You do this in Fiddlers options under Tools > Options > HTTPS.

This will prompt you to install a certificate that Fiddler uses to terminate SSL in Fiddler so it can show you the decrypted traffic.

One You have completed this you need to export the certificate Fiddler installed so that you can set up Storage Explorer with it.

As you go through the wizard choose “Base-64 encoded X.509 (.CER)” for the file format

Save it your desktop or somewhere you will be able to find it later

Setting up Azure Storage Explorer

First up you need to configure Azure Storage Explorer to use Fiddler as a proxy. This is pretty straightforward.

In Storage Explorer go to the Edit -> Configure Proxy menu and add 127.0.0.1 and 8888 (fiddler defaults). Note: Not authentication should be used.

Now Storage Explorer will use Fiddler … however, you will start getting “unable to verify the first certificate” errors as Storage Explorer still doesnt trust the root certificate that fiddler is using for SSL termination.

To add the Fiddler certificate go to the Edit > SSL Certificates > Import Certificates. Pick the .cer file you saved out earlier. Storage Explorer will prompt you to restart in order for these to take effect.

Now when you start using Storage Explorer you should start seeing its traffic in Fiddler and in a readable decrypted state like below.

Now you can navigate around and do various operations and see what and how Azure Storage Explorer is doing it.

One of the most interesting announcements, at least in my mind, this week from Ignite 2016 was the news that Microsoft is adding support for Microsoft Graph API in hybrid deployments.

This means you can call the Microsoft Graph API like you would normally for Office 365 based mailboxes, for example, but have it actually connect with a mailbox that resides in an on-prem exchange server!

Let that sink in for a moment. That is pretty sweet!

Typically, if you have an application that is not deployed behind the firewall, i.e. inside the orgnaizations network, you couldnt call things like SharePoint or Exchange APIs without doing network gymnastics like VPN, reverse proxy or putting holes in your firewall (yuk).

Now with this hybrid support in the graph you can simply call internet based REST APIs and Microsoft is doing the work of facilitating that communication back to the on-prem resource.

Currently in Preview the graph only supports Mail, Calendar and Contacts in this hybrid configuration right now, however I can only imagine that more support for other endpoints like Users, SharePoint etc… will come at some point.

You also have to have Exchange 2016 CU3 servers deployed on-prem to get this support and sync your AD to Azure AD as authentication is managed this way.

You can read more about these re-reqs here: http://graph.microsoft.io/en-us/docs/overview/hybrid_rest_support

I think this is a huge benefit for those who are looking to build applications or cloud services that connect to data wherever that sits.

Couple of interesting scenarios to think about:

Mobile app that works outside the firewall was either not possible or too hard due to connectivity issues.

Cloud service web apps that you want to connect to on-prem data

Tools and Apps that can now work with data either in Office 365 or on-prem

This to me is a huge step in the right direction for Microsoft in their quest to make developers lives better in a hybrid world.